Work machines such as excavators, backhoes, front shovels, and the like are used for excavation work. These excavating machines have work implements which consist of boom, stick and bucket linkages. The boom is pivotally attached to the excavating machine at one end, and its other end is pivotally attached to a stick. The bucket is pivotally attached to the free end of the stick. Each work implement linkage is controllably actuated by at least one hydraulic cylinder for movement in a vertical plane. An operator typically manipulates the work implement to perform a sequence of distinct functions which constitute a complete excavation work cycle.
The earthmoving industry has an increasing desire to automate the work cycle of excavating machines for several reasons. Unlike a human operator, an automated excavating machine remains consistently productive regardless of environmental conditions and prolonged work hours. The automated excavating machine is ideal for applications where conditions are dangerous, unsuitable or undesirable for humans. An automated machine also enables more accurate excavation making up for any lack of operator skill.
A lot of effort has gone into developing the automatic excavation algorithms. In this development, the digging and therefore the bucket position is described relative to the excavator car body. As long as the car body sits horizontally on the ground (no tilt or pitch) the computations can be made to determine the bucket location provided that the car body location is known. As the orientation of the excavator changes additional sensors are added to determine the pitch and roll to compensate. Often a laser system is used to determine the elevation of the body and multiple detectors on the car body are used to determine orientation. Still there is no information available as to the x,y location of the excavator within the work site.
The present invention is directed to overcoming one or more of the problems set forth above.